1. Field of the Invention
This invention relates generally to animals and animal nutrition. More specifically, this invention relates to treating arthritis and joint discomfort in dogs by use of dietary supplements.
2. Related Art
Degenerative joint diseases or arthroses are conditions where degenerative changes in cartilage lead to a breakdown in the integrity of the structural matrix of cartilage or tendinous tissues. Conventionally referred to as arthritis, the complaints associated with the degenerative changes occur most frequently in aged individuals.
Arthritis is much more common in dogs than other domesticated pets. Arthritis is a terrible disease, as it causes pain and restricts mobility. Any dog can be afflicted with arthritis, although older dogs and larger breeds can be more susceptible. Active dogs, like work or hunting dogs, may also be at greater risk because of their increased activity levels.
Arthritis affects primarily the weight bearing joints (hips, knees, etc.) and the joints of the toes. Symptoms include early morning stiffness, stiffness following periods of rest, pain that worsens on joint use, and loss of joint function.
Arthritis can take one of several forms.                1. Hip dysplasia is a malformation of the hip sockets that allows excessive movement in the joint, causing chronic inflammation and thus furthers breakdown and the deposition of calcium.        2. Dislocation of the kneecap is a malformation of the leg bones such that the kneecap is repeatedly pulled out of position, thus slipping back and forth and causing continuous low-grade inflammation. This is a condition seen in small breeds and is related to low-quality food and poor breeding.        3. Degeneration of the shoulder joint involves the breakdown of cartilage in this joint, leading to inflammation and pain on movement. This is a condition often seen in medium to large breeds.        4. Arthritis of the elbow is a condition that is caused by improper bone formation and is considered by many in the field to be hereditary. It is generally seen in German shepherds. Nutrition, however, may be a more significant factor than generally understood.        5. Swelling and pain in the leg joints is a condition seen in young dogs (a few months in age) of the large breeds that is apparently due to inadequate formation of vitamin C and is the result of heredity and poor nutrition.        
Cartilage provides the cushion and frictionless mobility of joints. Comprised of two key components, collagen and glycosaminoglycans (GAG), cartilage is constantly under a process of natural repair and regeneration. Because of overuse, injury or other causes, many individuals overwhelm their body's ability to keep up with the natural process of repair. The result is cartilage which becomes increasingly dry and inflexible leading to pain and eventual joint restriction.
The pathogenesis of arthroses is by no means an inevitable phenomenon of aging, as a healthy joint is capable of functioning for a lifetime. In medical science, a differentiation is made between primary and secondary arthroses. Secondary arthroses develops from known precedent diseases, whereas primary arthroses is not known to develop from any determinable basic disease. Rather, cases of primary arthroses disease manifest in an imbalance between mechanical stress and mechanical resistance of the joint cartilage.
A predisposition to arthritis can be passed to a dog during its fetal development. Many of the more common joint health problems can be avoided by providing adequate nutrition for females throughout their pregnancy. Adequate fetal nutrition can help offset the expression of genetics.
For most dogs, age-related concerns of use and overuse are more common than genetic factors. If one considers the activity level of most dogs, the wear and tear on their joint tissues can be exceptional. Although the body has natural mechanisms for repairing joint tissues as well as cartilage, age and excessive wear can exceed the pet's repair mechanisms. Once damage exceeds repair, there is often an increase in inflammation and a vicious cycle is set into play, further restricting repair.
Although many drugs can be used to treat the symptoms of arthritis, the only sure-fire way to break the cycle of damage is to support the pet's natural cartilage repair systems. This can be accomplished by supplementing the dog with additional nutrition targeted at supporting cartilage repair and joint health.
The conservative treatment measures in the cases of coxarthroses and gonarthroses, and operative measures such as artificial joint prosthesis, are sufficiently known.
Steroids such as corticosteroids, and other anti-inflammatory materials such as non-steroidal anti-immflamatories (NSAIDs) and high doses of aspirin, are widely used for the treatment of these ailments (Pharmocol. Res. Commun. 10 557-569 (1978) by Vidal et al). While these materials often relieve the pain and swelling associated with maladies arising from connective tissue problems, they offer no support for repair processes. Furthermore, NSAIDs may also inhibit the body's own natural healing processes, leading to further deterioration of the connective tissue.
The activity of chondrocytes (cartilage cells) is regulated by factors including the level of intracellular ions. Up-regulation of chondrocytes, in combination with the presence of GAG building blocks, produces repair of cartilage tissues under normal and arthritic conditions.
Bone, or osseous tissue, is a rigid form of connective tissue that constitutes most of the skeleton of higher vertebrates. The intercellular matrix of bone contains an organic component, chiefly collagenous fibers, and an inorganic component that accounts for approximately two thirds the weight of bone. The inorganic component are the salts responsible for the hardness and rigidity of the tissue. The collagenous fibers contribute greatly to the strength and resiliency of bone.